Combination chassis and loudspeaker



June 10, 1958 H. F. OLSON ET AL 2,838,607

COMBINATION CHASSIS AND LOUDSPEAKER Filed April 27, 1951 2 Sheets-Sheet 1 .Tune 10, 19 58 .H. F. OLSON ETAL 2,

. COMBINATION CHASSIS AND LOUDSPEARER Filed April 27, 1951 2 Sheets-Sheet 2 I -Jf I, ,1 I I ATT NEY 2,83 8,607 COMBINATION CHASSIS AND 'LOUDSPEAKER Harry F. Olson, Princeton, and John Preston, Metedeconk, N. J assignors to Radio Corporation of America, a corporation of Delaware Application April 27, 1951, Serial No. 223,388

4 Claims. (Cl. 179-1) This invention relates to a combination chassisand loudspeaker. More particularly it relates tothe type of loudspeaker in which the dishpan or part of the diaphragm support serves as the magnetic return path. j

In prior art speakers employing dishpans,-little change .in the ordinary cone type of speaker has been made. Most of the effort'has been directed toward reducing the number of parts necessarvfor-the construction of the speaker itselftand no effort has been made to, fabricate the speaker and chassis asa-Iunitary structurewhereinfla part of the chassis'functions asa part of the speaker. Our invention is directed toward'that end.

T he combination speaker and chassisSdisclosedherein r is a unitary structure. A minimum numberof parts. in

the speaker construction is employed, and. the construc: tion offers a. wide-rangeof possibilities for-design to secure compactness. According to our. improvement," the chassis may be made of any magnetic metal, such as cold United Stat s ati rolled steel. By utilizing part of the chassis for the mag netic path of the speaker and part of the chassis for-supporting the speaker parts, we have simplified the-Aloudspeaker tothe extent that approximatelyEone-half of .the

coil form; 2 8 is extended rearwardly from the speakerdiaphragm-or cone 27,gand said voice coil 28 is thereby posiparts ordinarily used in chassis and speaker construction have been eliminated. I V

A primary object .of our invention, therefore,. is.to

provide a combined support and'magnetic pathfor the speaker parts.

3 A second object of our invention' is to avoid the necessity of using a separate mounting for" attaching a loudspeaker to a radio or audio chassis.

Another object of our invention is to increase the efficiency of a loudspeaker by reducing the leakage flux in the magneticpath.

A further object of our invention is to provide a loudspeaker which will be economical and easy to manufacture, with improved performance. i

' invention we have proahd magnet support. The diaphragm supporting portion of the sheet is return bent toform an open U shapede'sig'ned to receive a speaker magnet, the side and bottomwall's of the U shape constituting the magnetic return path of the magnet. The magnetic material referred to in this paragraph and throughout this specification and the appended claims is of the class of substances usually referred to as ferromagnetic, but which do not become permanently magnetized, that is, have low or negligible retentivity. 7

Our invention, both as to its structure and operation, together with additional objects and advantages thereof, will be'understood best by reference to the following specifications when read in connection withthedrawing, in which: I

Figure l is a perspective view of the chassis, speaker support, and magnetic structure of one form of our invention;

Figure 2 is an elevation of the embodiment of our in- 5% is attached to the inner face 23 and the voice coil 2,838,607 Patented June 10, 1958 vention taken along a center section of Figure 1, with additional parts to form a complete speaker;

Figure 3 shows an end elevation in section of a modification of our invention in the form of a fiat type chassis;

Figure 4 is a side elevation of the modification illustrated by Figure 3; and

Figure 5 is a perspective view of a completed radio employing our invention. I

Referring continuously tothe drawings, in which like reference numerals in the several figures designate similar parts: I r

In Figure 1, there is illustrated a plate 11, which may be either base, or a side or a top plate, but which for convenience of reference is called herein a base plate, which is adapted to have mounted thereon various radio and audio components. For this purpose, apertures 12 are provided in the plate 11.

Extending upwardly from the base plate 11 is a diaphragm mounting member 13 having an opening 15 therein to receive the diaphragm of the loudspeaker.

. The diaphragm mounting member 13 is bent laterally to form a support 17 to form a magnet receiving part. The end of the support 18 is bentdownwardly and then is return bent,,giving a U-shaped magnet receiving receptacle; 'A ma gnet19,;which may be eit her a permanent v magnet or electromagnet is rigidly secured to the back 7 face 21, and extends into an aperture 22 in the inner face "embodiment of our invention shown in Figure 1, it will heseen that a cone 217 and the voice coilmembershave beenladded. The cone '27 is provided with a conventional voic e coil-form 2j carrying a voice coil 29. The'voice tioned in the air gap between the pole piece 31 of the magnet 19 and the aperture 22 in the inner face 23 of the magnet receiving receptacle 21, 23 and 24.

A magnet centering cup 33 of non-magnetic material is rigidly secured on theinner face 21 of the magnet receptacle to position the-polepiece 31in the aperture 22.

-A keeper 35 may beutilized to keep the pole piece31 andthe. magnet 19 in contact with the inner face of the hack face 21 of the magnet receptacle. A centering spider form 28 to align the voice coil 29 in the air gap between the pole piece 31 and the aperture22.

Referring to Figures 3 and 4 it will be seen that instead of an upright form of chassis and loudspeaker, a

. flattype has been provided. This type includes a chassis platform 25 in which is provided an opening for the pole v piece 31 and voice coil form 28. The edges of the chassis platform 25 are bent downwardly to form supporting sides 30. One of;these sides 30 is provided with an extend por on 7. wtin d1 n d qs a le t but spaced from the chassis platform 25. This extending portion 37 may stop short of the opposite side of the chassis. For the sake of rigidity, the extended portion 37 may continue across to the opposite side and be secured thereto.

Thespeaker cone 27 is secured to the upper face of the chassis platform 25 over the opening therein withthe V concave portion of the speaker cone 27 facing inwardly or downwardly toward the chassis platform 25. Because of this arrangement the voice coil form 28 is carried in the concave portion of the diaphragm or cone 27 and ex- -tends inwardly or downwardly into the opening provided in the chassis platform 25. A space is provided between the edges of the opening and the pole piece 31 of the magnet 19 to provide an air gap in the magnetic path a'sep'aratemounting arrangement.

f magnet 19. The remainder of the magnetic path is composed of chassis platform 25, the supporting side 30, and the extended portion 37.

Radio and audio components 38, such as tubes, transformers, and the like, may be-mounted on the upper portion of the chassis platform 25 in the conventional man ner; Resistors, capacitors, and other circuit components would be mounted inside the chassis, also in the usual 'manner.

In Figure 5, there is shown a completed radio of the compact table model type made'in accordance with our invention. In this figure are shown the radio and audio components 38 mounted on the base plate 11 of the chassis shown in Figures 1 and 2. An output transformer speaker and chassis indicates that our invention has an equal quality of sound reproduction.

The amount ofsteel used-in our invention is considerably less for several reasons. Inthe first place, mounting brackets, bolts andnuts are unnecessary. Secondly, parts are 'not duplicated. Thirdly, the steel parts in our combination loudspeaker and chassis perform two functions: that of supporting and mounting the loudspeaker assembly, and providingthe magnetic path. I

It will be apparent from the description of our improved combination loudspeaker and chassis that it is compact and simple to manufacture and that it eliminates Although, we have illustratedand described several embodiments-of our invention, itwill undoubtedlybe apparent to those skilled in the art that many other forms thereof, as well as variations in those shown, are possible without departing from the spirit of our invention or the scope of the appended claims.

We claim: a

1. A combination loud speaker and chassis comprising a unitary magnetic chassis-formed by bending a single sheet of magnetic material so as' to provide at least a first and second face in spacial, substantially parallel relationship, said first face having an aperture therein, a third parallel face interposed between said first and second faces and havingan aperture therein, a diaphragm having its outer periphery contiguous with said first face in axial alignment with saidapertures, a voice coil form secured to said diaphragm and extending toward said second face through saidaperture in said third face and spaced apart therefrom, a voice-coil on said form, and a magnet mounted on said second face extending into a region of magnetic cooperation with said voice coil.

2. A combination loud speaker and chassis comprising a unitary magnetic chassis formed by bending a single sheet of magnetic material so as to provide. at least a first and second-face in spacial, substantially parallel relationship, said first face having an aperture therein, a third parallel face interposed between said first and second faces and having an aperture therein, a diaphragm having its outer periphery contiguous with said first face in axial alignment with said apertures, a voice coil form secured to said diaphragm and extending toward said second face, through said aperture in said third face and spaced apart therefrom, a voice coil on said form, a magnet mounted on said second face and having a pole tip thereon extending into a region of magnetic cooperation with said voice coil, and a centering member mounted on said third face and connected to said voice coil form to hold said voice coil form in spacial alignment with said pole tip.

3. A combination loud speaker and chassis comprising a unitary magnetic chassis formed by bending a single sheet of magnetic material so as to provide at least a first andsecondface in spacial, substantiallyparallel relationship, said first face having an aperture therein, a third parallel face interposed between said first and second faces and having an aperture therein, a diaphragm having its outer periphery contiguous with said first face in axial alignment withsaid apertures, a voice coil form secured to said diaphragm and extending toward said second face, through said aperture in said third face, and spaced apart therefrom, a voice coil on said form, a magnet mounted on said second face and having a pole tip thereon, said pole tip extending into a region of magnetic cooperation with said voice coil, and a keeper mounted on said pole tip and connected to said third face to maintain a uniform air gap therebetween.

4. A combination loud speaker and chassis comprising a unitary magnetic chassis formed by bending a single sheet'of magnetic material so as to provide at least a first and second face in spacial, substantially parallel relationship, said first face having an aperture therein, a third parallel face interposed between said first and second faces and having an aperture therein, a diaphragm having its outer periphery contiguous with said first face in axial alignment with said apertures, a voice coil form secured to said diaphragm and extending toward said second face, through said aperture in said third face, and

spaced apart therefrom, a voice coil on said form, a magnet mounted on' said second face and having a pole tip thereon, said pole tip extending into a region of magnetic cooperation with saidvoice coil, a keeper mounted on said pole tip and connected to said third face to maintain a uniform air gap therebetween, and a centering member on said third face connected to said voice coil form to hold said voice coil in spacial alignment with said pole tip.

References Cited in the file of this patent UNITED STATES PATENTS 

